Essential information for decision makers in the frame of a radiological emergency response is expected to be derived from radiological maps. In the case a spatial interpolation step is needed, one has to choose among many algorithms that may generate very different results. The maps produced can be of mainly two forms: they can present either estimates of the radiological variable at unsampled locations, or estimates of the local probability of the variable to exceed a threshold (risk maps) defined usually by a regulatory standard. Inevitably, the whole mapping procedure involves various types and levels of uncertainties and one may ask how reliable is the delineation of the areas and shapes of the zones identified as polluted. It is the purpose of this paper to discuss some of the main sources of uncertainties that are attached to radiological risk maps by means of a case study as well as how these uncertainties may affect the overall decision process.